Semiconductor dice are used to construct various semiconductor components, such as semiconductor packages and multi chip modules. These semiconductor components typically include a substrate on which bare semiconductor dice are mounted. For example, conventional plastic semiconductor packages can include substrates in the form of metal leadframes. During a packaging process the bare dice are attached and electrically connected to the leadframes, and then encapsulated in a plastic resin.
Besides leadframes, other types of substrates are used to construct semiconductor components. For example, other types of semiconductor packages, such as "BGA packages" and "chip scale packages", include substrates which can comprise a glass filled plastic, such as FR-4, or FR-5, or in some cases silicon, or ceramic. Multi chip modules and circuit boards, can also include plastic, silicon, or ceramic substrates, on which semiconductor dice, as well as other electronic components, are mounted.
During fabrication of a semiconductor component the dice are attached to the substrate. One method for attaching the dice to the substrate is by forming an adhesive layer between the dice and the substrate. For example, die attach adhesives, such as epoxy and silicone, can be used to back bond dice to substrates. Typically, the adhesive is dispensed in viscous form from a pressurized nozzle, and then cured to harden. However, for some applications it is not practical to use an adhesive because the viscous material may undesirably adhere to the surfaces of bond pads, and other electrical elements on the die or substrate, and adversely affect the electrical characteristics of the component. Also for some applications, it may not be possible to uniformly form the adhesive layer with a required planarity and geometrical configuration.
Another technique for attaching dice to lead frame substrates employs adhesive tape. For example, during fabrication of a lead-on-chip semiconductor package, semiconductor dice are attached to a metal leadframe using double sided adhesive decals. With a typical lead-on-chip fabrication process the decals are punched with a required peripheral configuration from a length of tape. Portions of the tape that do not become part of the decal are then discarded.
While adhesive tape has been used successfully in the manufacture of plastic semiconductor packages constructed with metal lead frames, it has typically not been used in the volume manufacture of other types of semiconductor components. The present invention is directed to a method and system for fabricating various types of semiconductor components using adhesive tape to attach one or more semiconductor dice to a substrate. In addition, the present invention makes decals without wasted tape, and with accurate alignment of the decal, the substrate, and the die to one another.